VBA Open any workbook - vba

Question

I have a macro that opens a spreadsheet from a specific folder and saves the output to a worksheet called Sheet1 in another workbook. The macro works if the file name is called "MyFile.xls" but i would like it to be able to run on any file name but it must have a "Book2" worksheet.
Here is my code:
Dim source As Workbook
Dim output As Workbook
Dim sourceSheet as WorkSheet
Dim outputSheet as WorkSheet
Dim file As String
file = "C:\Spreadsheets\MyFile.xls" 'I would like it to handle any files from any location'
Set output = ThisWorkBook
output.Activate
If Len(Dir$(file)) > 0 Then
Set source = workbooks.Open(file)
Set sourceSheet = source.Worksheets("Book2") 'Must only run if the sheet is called Book2'
Set outputSheet = output.Worksheets("Sheet1") 'Saves sheets into a new sheet called Sheet1'
End Sub

Answer 1

Is this what you are trying? (TRIED AND TESTED)
Sub Sample()
Dim source As Workbook, output As Workbook
Dim sourceSheet As Worksheet, outputSheet As Worksheet
Dim File
'~~> Show a dialog to open any excel file
File = Application.GetOpenFilename("Excel Files (*.xls*), *.xls*")
If File = False Then Exit Sub
Set output = ThisWorkbook
If Len(Dir$(File)) > 0 Then
Set source = Workbooks.Open(File)
'~~> Error check to see if the workbook has that sheet
On Error Resume Next
Set sourceSheet = source.Worksheets("Book2")
If Err.Number = 0 Then
Set outputSheet = output.Worksheets("Sheet1")
'
'~~> Rest of your code
'
Else
MsgBox "Not found"
source.Close SaveChanges:=False
End If
On Error GoTo 0
End If
End Sub